Tulipa L. is a genus of significant economic, environmental, and cultural importance in several parts of the world. The exact number of species in the genus remains uncertain due to inherent taxonomic challenges. We utilized next-generation sequencing technology to sequence and assemble the plastid genomes of seven Tulipa species collected in Kazakhstan and conducted a comparative analysis. The total number of annotated genes was 136 in all seven studied Tulipa species, 114 of which were unique, including 80 protein-coding, 30 tRNA, and 4 rRNA genes. Nine regions (petD, ndhH, ycf2-ycf3, ndhA, rpl16, clpP, ndhD-ndhF, rpoC2, and ycf1) demonstrated significant nucleotide variability, suggesting their potential as molecular markers. A total of 1388 SSRs were identified in the seven Tulipa plastomes, with mononucleotide repeats being the most abundant (60.09%), followed by dinucleotide (34.44%), tetranucleotide (3.90%), trinucleotide (1.08%), pentanucleotide (0.22%), and hexanucleotide (0.29%). The Ka/Ks values of the protein-coding genes ranged from 0 to 3.9286, with the majority showing values <1. Phylogenetic analysis based on a complete plastid genome and protein-coding gene sequences divided the species into three major clades corresponding to their subgenera. The results obtained in this study may contribute to understanding the phylogenetic relationships and molecular taxonomy of Tulipa species.

Background. Tulipa species are economically, culturally, scientifically, and ecologically important. Tulips present taxonomic complexities that cannot be adequately resolved by examining their morphological characteristics alone or by relying on a limited selection of genetic markers. Methods. In the present study, we assessed the complete plastid sequences of Tulipa alberti Regel and Tulipa greigii Regel collected from Kazakhstan. Additionally, 14 previously published plastomes were obtained from GenBank for comparison and phylogenetic analysis. Results. The plastid genome sizes of T. alberti and T. greigii were 152,359 bp and 152,242 bp, respectively. In the plastid genomes of T. alberti and T. greigii, 136 genes were annotated, 114 of which were unique. These unique genes comprised eighty protein-coding, thirty transfer RNA, and four ribosomal RNA genes. Additionally, 415 simple sequence repeats were identified, comprising 107 tandem, 40 forward, 49 palindromic, 8 reverse, and 1 complementary repeat. Notably, the region containing ycf1 exhibited high variability and may serve as an informative DNA barcode for this genus. Conclusion. Phylogenetic analysis showed strong support for the relationships among Tulipa species, indicating the utility of plastid genome data for further taxonomic studies within the genus.

The genus Tulipa L., renowned for its ornamental and ecological significance, encompasses a diversity of species primarily concentrated in the Tian Shan and Pamir-Alay Mountain ranges. With its varied landscapes, Kazakhstan harbors 42 Tulipa species, including the endangered Tulipa alberti Regel and Tulipa greigii Regel, which are critical for biodiversity yet face significant threats from human activities. This study aimed to assess these two species’ genetic diversity and population structure using 15 expressed sequence tag simple sequence repeat (EST-SSR) markers. Leaf samples from 423 individuals across 23 natural populations, including 11 populations of T. alberti and 12 populations of T. greigii, were collected and genetically characterized using EST-SSR markers. The results revealed relatively high levels of genetic variation in T. greigii compared to T. alberti. The average number of alleles per locus was 1.9 for T. alberti and 2.8 for T. greigii. AMOVA indicated substantial genetic variation within populations (75% for T. alberti and 77% for T. greigii). The Bayesian analysis of the population structure of the two species indicated an optimal value of K = 3 for both species, splitting all sampled populations into three distinct genetic clusters. Populations with the highest level of genetic diversity were identified in both species. The results underscore the importance of conserving the genetic diversity of Tulipa populations, which can help develop strategies for their preservation in stressed ecological conditions.